1. Field of the Invention
This invention relates to a process for making a minute hole in a wall of a metal article such as thin sheet metal.
2. Description of the Prior Art
There presently exists many processes for forming a minute hole in thin sheet metal. Such prior art processes include, for example, electro-discharge machining, electron beam machining, and laser beam machining.
However, such processes necessitate the use of costly equipment and/or are inefficient in operation. For example, in electro-discharge machining, wherein a minute hole is formed in a thin wall directly by an electrode, high electrode consumption is an expensive problem. The electron beam machining technique suffers from poor operational efficiency in that the machining must be performed in a vacuum. The laser beam machining process obviously requires very expensive equipment. Hence, the foregoing techniques lead to low efficiency in operation, and thus an increase in the unit cost of forming a minute hole.